When
3:45 p.m., Sept. 22, 2015
Where
Kuiper Space Sciences 312
Dr. Lucille Le Corre
Research Scientist
Planetary Science Institute
Asteroids Are Not Pristine: Lessons From NASA’s Dawn Mission to Asteroid Vesta
Asteroids are thought to be remnants of planetary formation providing us with pristine samples that recorded conditions in the early Solar System. However, recent observations of asteroid Vesta, the largest differentiated asteroid in the main asteroid belt, by NASA's Dawn mission shows a surface that is far from pristine. The Framing Camera onboard the Dawn spacecraft acquired images of the entire surface of the asteroid in clear and seven narrow band filters (from 0.4 to 1 microns). We have identified several units on Vesta that are evidence for exogenic contamination of the surface including low reflectance units (dark material). By comparing Dawn data with meteoritical data, we inferred that the dark material corresponds to remnants of carbonaceous chondrite impactors. Similarly, several recent studies suggested that the mineral olivine was detected on the surface of Vesta. These publications proposed that olivine was excavated from the mantle of asteroid Vesta during the formation of a large impact basin at the South Pole. Our reanalysis of Dawn data and meteoritical evidence suggests that this olivine might be exogenic ordinary chondrite impactors rather than mantle olivine.
Host: Dr. Michael Nolan
Research Scientist
Planetary Science Institute
Asteroids Are Not Pristine: Lessons From NASA’s Dawn Mission to Asteroid Vesta
Asteroids are thought to be remnants of planetary formation providing us with pristine samples that recorded conditions in the early Solar System. However, recent observations of asteroid Vesta, the largest differentiated asteroid in the main asteroid belt, by NASA's Dawn mission shows a surface that is far from pristine. The Framing Camera onboard the Dawn spacecraft acquired images of the entire surface of the asteroid in clear and seven narrow band filters (from 0.4 to 1 microns). We have identified several units on Vesta that are evidence for exogenic contamination of the surface including low reflectance units (dark material). By comparing Dawn data with meteoritical data, we inferred that the dark material corresponds to remnants of carbonaceous chondrite impactors. Similarly, several recent studies suggested that the mineral olivine was detected on the surface of Vesta. These publications proposed that olivine was excavated from the mantle of asteroid Vesta during the formation of a large impact basin at the South Pole. Our reanalysis of Dawn data and meteoritical evidence suggests that this olivine might be exogenic ordinary chondrite impactors rather than mantle olivine.
Host: Dr. Michael Nolan
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